US3552181A

US3552181A - Impulse-forming and like machines

Info

Publication number: US3552181A
Application number: US689820A
Authority: US
Inventors: Lin Tak Chan; Stephen Albert Tobias
Original assignee: National Research Development Corp UK
Current assignee: National Research Development Corp UK; National Research Development Corp of India
Priority date: 1966-12-13
Filing date: 1967-12-12
Publication date: 1971-01-05
Anticipated expiration: 1988-01-05
Also published as: GB1204487A; FR1550530A; CH505658A

Abstract

AN IMPULSE-FORMING, FORGING OR LIKE MACHINE IS OF THE KING IN WHICH THE MOVING MEMBER IS MOVED BY PRESSURE OF A GAS, POSSIBLY AIR, APPLIED INITIALLY TO A SEALED PORTION OF THE OPERATING AREA OF A PISTON MEMBER ASSOCIATED WITH THE MOVING MEMBER, THE SEAL BEING BROKEN SUBSEQUENTLY TO ENABLE THE PRESSURISED GAS TO BE APPLIED SUDDENLY TO SUBSTANTIALLY THE FULL OPERATING AREA OF THE PISTON TO CAUSE SAID MOVING MEMBER TO BE IMPULSED, AND THE MACHINE IS ARRANGED FOR OPERATION WITH A SUBSTANTIALLY UPWARD IMPACTING STROKE OF THE MOVING MEMBER SO THAT GRAVITATIONAL FORCES PROVIDE AT LEAST PART OF THE EFFORT OF RETURNING THE MOVING MEMBER AND ITS PISTON MEMBER TO THEIR INITIAL SET POSITIONS. USE IS MADE POSSIBLE OF SO SHAPING THE PISTON MEMBER AS TO FORM OIL RESERVOIRS FOR LUBRICATING THE PIS-

TON, DUCTS MAY BE PROVIDED, LEADING FROM SAID RESERVOIRS TO THE VICINITY OF THE PISTON RINGS.

Description

Jan. 5, 1971 UN TAK CHAN EI'AL 3,552,181

IMPULSE-FORMING AND LIKE MACHINES Filed Dec. 12, 1967 US. or. 1z-4s0 6 Claims ABSTRACT OF THE DISCLOSURE An impulse-forming, forging or like machine is of the kind in which the moving member is moved by pressure of a gas, possibly air, applied initially to a sealed portion of the operating area of a piston member associated with the moving member, the seal being broken subsequently to enable the pressurised gas to be applied suddenly to substantially the full operating area of the piston to cause said moving member to be impulsed, and the machine is arranged for operation with a substantially upward impacting stroke of the moving member so that gravitational forces provide at least part of the effort of returning the moving member and its piston member to their initial set positions. Use is made possible of so shaping the piston member as to form oil reservoirs for lubricating the piston; ducts may be provided, leading from said reservoirs to the vicinity of the piston rings.

a This invention relates to impulse-forming machines of the kind in which a moving member is moved by pressure of agas, possibly air, applied initially to a sealed portion of the operating area of a piston member associated with the moving member, the seal being broken subsequently to enable said pressurised gas to be applied suddenly to substantially the full operating area of the .piston to cause said moving member to be impulsed. It is intended that the term impulse-forming machine shall include forging and like machines. Such a machine is described in Pat. No. 3,253,399 and in that machine the energy derived from release of chemical energy of a material, for example by combustion, is caused to be applied first to the piston member over part only of its area against a back pressure on the piston member; when the energy thus applied to the piston member overcomes the back pressure the piston member moves and a seal is broken, whereupon the energy of the combusted gases is exerted over the full area of the piston member, which then moves under a sudden impulse to cause the required movement of the moving member of the machine.

Where in such machines as have been proposed, and certainly in the machine described in the aforesaid patent application, the impulsed moving member has been arranged to perform its work function in the downward direction, it is necessary to provide means for lifting the said moving member to return it to the position where the seal is re-made; further work is necessary to provide the back pressure on the seal. Since, in many cases, the weight of the moving member is combined with the weights of massive platens and/or guide members and dies, tools or the like, the amount of work involved in returning these to the initial position and to retain them in the sealed condition, can be very great. In some machines it is essential that the working stroke of the machine is downwards and the return conditions are inevitable. However, it is not always paramount that the working stroke should be in this direction and according to the present invention a machine of the kind described is adapted for a substantially upward United States Patent impact stroke. In that case, it will be seen that not only is the weight factor of the return stroke relieved but the weight of the moving parts essentially assists the return travel. In fact, this weight may be used at least to assist in retaining the piston member against its seal with the energy chamber. If necessary, of course, additional pressure may be provided for maintaining the seal and for this purpose the piston member may be backed by compressed gas(es), such as air, as with the downstroke machine, but in this case any necessary additional pressure can be appreciably less than that pressure that would be required were the stroke to be downward.

According to a feature of the invention, because it is, in effect, inverted, the piston member may be so shaped, on its surface remote from its surface associated with the seal, that it provides one or more oil reservoirs that may be used, in conjunction with feed holes through the piston member, such as through a skirt thereon, to provide oil for lubricating the piston ring(s).

In the case of combustion methods of producing the energy for the power stroke, re-charging of the energy chamber may be arranged to take place during the downward stroke so that the energy of the moving system on the return stroke is absorbed in compressing or assisting in compressing the new charge to be fired for the next working stroke.

There is also a possibility that the arrangement may be adapted to operate automatically on the diesel principle, though in that case the timing of fuel injection and of oxidant admission would need to be controlled with a certain degree of accuracy.

In a piston and cylinder arrangement in accordance with the present invention, the piston head may be so shaped, or may be provided with an attachment so shaped as to render sealing with the opening from the combustion chamber as set out in Pat. No. 3,253,399 more positive.

The connection between the piston and the impulsed member of the machine may be hollow and may serve to house ancillary gear such as, in the case of a blanking press, ejector gear for the stampings.

The impulsed member of an impulse machine embodying the invention preferably operates in conjunction with hydraulic, or pneumatic, follower rams which serve to catch the moving parts at or near the start of the return stroke, thus preventing excessive energy in the return stroke because of a bouncing effect by the working impact.

An ideal application of the invention is to an upwardly acting cropping machine, but other applications will be apparent to those skilled in the art.

One embodiment of the invention will now be described by way of example with reference to the accompanying drawing which illustrates in partial central section an upward stroke impulse-forming machine impulsed under the influence of the firing of a petrol/air charge in a combustion chamber.

In the drawing, the cylinder 1 of the petrol-driven device provides a guide for the piston 2 which has sealing rings 3 and is supported by the hollow connection 4 to the bottom platen 5 which moves with the piston and co-operates with fixed platen 6. The connection 4 is arranged to slide in the plate 7 which closes the end of cylinder 1, a packing 8 being provided to seal the sliding joint. The platen 5 slides on four pillars 9 which support the upper platen 6 in relation to the base member 10 on which cylinder 1 is mounted. The base 10 is supported in turn on a welded fabricated frame 11 to which it is secured; two rows of preloading bolts 12, 12' are provided to ensure that at least certain of the welds of the frame are in compression.

The lower end of the cylinder 1 is closed by a plate 13 which has a central aperture 14 forming an extension of a combustion chamber 15 which in turn has a head 16. The combustion chamber is provided with an inlet valve, an exhaust valve and a fuel injection and ignition arrangements so as to enable the device to operate on the lines described in the specification of Pat. No. 3,253,399 the piston crown is provided with an extension 17 which has a seating that makes substantially gas-tight contact with a seating 18 on the plate 13 to seal the combustion chamber.

The piston is shaped to provide an oil pocket 19 and holes 20 extend from this pocket to each ring groove to provide for adequate lubrication of the rings 3.

The hollow connection 4 provides accommodation for the pneumatic, or hydraulic, ejector device 21 for use for ejecting dies or stampings, or both, from the seating 22 in the lower platen 5, thus providing a compact arrangement.

Holes 23 in the plate 7 are provided for the passage of air from the space in the cylinder 1 as the piston 2 impulses under the action of the combusted charge.

As the piston moves impulsively upwards, so it moves the platen 5 with it and pneumatic, or hydraulic,

rams

24, 24 are arranged to be operated in sequence to follow the platen 5 and to catch it on the downward return stroke; in this way the downward stroke can be controlled. This movement takes place normally under the influence of the weight of the various masses. Another use for the rams 24, 24' is to inch the platen 5 for positioning purposes.

Arrangements, as will be evident, are made for exhausting the spent gases from the system and a new charge may be introduced during the downward, return, :stroke so that the final part of the stroke may be used to compress the new charge ready for the next firing.

It will be understood that the exhaustion of air through the vents 23 may be controlled by, for example, valve means; in this way some additional control may be exerted on the impulsive movement of the piston.

It will be further understood that, if desired, the cylinder may be pressurized above the piston in order to control the pressure on the seal 18; valves at the vents 23 would be a necessity in that case, and these may have to be opened in sequence to allow the air to escape during the impulse stroke of the piston. However, it may be arranged, if desired, that air above the piston is pressurised, or further pressurised, during the impulse stroke.

Other modifications or alternatives will be apparent to those skilled in the art.

We claim:

1. An impulse forming machine having at least one impulse part; a piston associated with and located below said impulse part; a cylinder for said piston; an energy chamber associated with and located below said cylinder and having an opening from said energy chamber into said cylinder wherein said opening is of substantially smaller cross sectional area than the operative area of the said piston; said chamber having at least one inlet orifice for the introduction into said chamber of fluid for use in impulsing said piston in a substantially upward direction; outlet means for exhausting fluid from said energy chamber; at least one vent in said cylinder towards the 0pposite end thereof to said energy chamber; sealing means on the piston for sealing that portion of the cylinder above the piston from that portion of the cylinder below the piston; an oil reservoir located in the piston; and feed means for feeding oil from the reservoir to the sealing means.

2. An impulse forming machine as claimed in claim 1 wherein the piston is formed with at least one annular peripheral recess;

the sealing means comprises a same number of piston rings located by said recess (es);

upper surfaces of the piston define an oil reservoir open to the upper portion of the cylinder; and

conduit means inclined in a generally downwards direction from the oil reservoir to the peripheral recess(es).

3. An impulse forming machine as claimed in claim 1 including an extension for the piston which extension is adapted to close against the opening from the energy chamber to the cylinder thereby to assist sealing of the energy chamber.

4. An impulse forming machine as claimed in claim 3 wherein said piston extension is adapted to at least partially enter said opening which presents an annular seating face to the piston extension.

5. An impulse forming machine as claimed in claim 1 including:

a plurality of fluid operated follower rams whereby said rams serve to catch said member near the start of the return stroke in order at least to assist in absorbing the energy of said member and said piston in said return stroke.

6. An impulse forming machine as is claim 1 wherein the piston is adapted to compress each new charge of combustible material in the energy chamber during the downstroke of the piston and the impulsed part.

References Cited UNITED STATES PATENTS 2,132,148 10/1938 Davis 26.1X 3,103,136 9/1963 Bollur 72453 3,205,790 9/1965 Bollur 72-453 3,209,578 10/ 1965 Muller 72-453 3,253,399 5/1966 Bakhtar 72453 3,267,717 8/1966 Reischer 72-453 3,311,049 3/1967 Hugi 72453 CHARLES W. LANHAM, Primary Examiner G. P. CROSBY, Assistant Examiner US. Cl. X.R.